I have some questions related to pumps for a solar heating system. Thanks for any help in advance.
I just installed a pool, and they installed two pumps:
pool: Jandy Zodiac FloPro FHPM 2.0-2 dual speed: HP 2.0 & 0.25
spa: Jandy Zodiac Stealth Pro Series, SHPF3.0 HP 3.0.
The pumpsí manuals, which include the flow rates based on the dynamic head are:
http://www.zodiacpoolsystems.com/~/medi ... /SA/SA6220
http://www.zodiacpoolsystems.com/~/medi ... H/H0573800
The spa 3.0 HP pump also runs a water feature in the pool with an overflow edge into a trough, which also functions as the skimmer. It turns on automatically 30 minutes per day.
The main pump is set up to only use the SWG when in 0.25 HP low-speed mode, although the installer said that it can be changed to run the SWG in high-speed mode too.
Currently I donít use the high-speed 2.0 HP mode of the pool pump. It is supposedly for using a cleaner, but I use a robotic plug-in cleaner - those seem to be much better and more energy efficient than the ones that run off the pool pump anyway.
I was looking to install a Heliocol solar heater. The installer suggested nine 4 x 12.5í HC 50 panels (450 ft2 total), with 2" pipes.
My pool/spa surface area: 290 ft2. Southwest exposure in South Florida, with reduced direct solar heat from a screen enclosure with extra sun blocking on some sides.
My roof is 22' above the pool level. The roof looks like it has a 30 degree slope. So assuming the bottom of the panels start 2' from the edge of the roof (I don't know where they actually will install them), the bottom of the panels will be 23' above the pool level, and the top of the panels will be 29.25' above the pool level.
According to the solar installer, 0.75 hp is needed for a 2-story home. So with my current pump, I might have to run the pump at high speed 2.0 hp constantly in order to get the water up there, as low speed is 0.25 hp. According to the pool installer, and he could be wrong, there is no way to tell the Aqualink control to use high-speed if the temperature drops below the solar heaters settings and to use low-speed otherwise. JasonLion wrong on a different post:
So maybe some automation systems can do that, so maybe Aqualink can. And even if there were a way to variably switch between high and low speed based on the solar heater's needs, that might make it difficult to set a SWG level, given that the SWG would be producing lower or higher levels based on the pump hp depending on the solar heater's needs. The solar heater and SWG's needs would be opposite: when things were colder outside, the pump would switch into high-speed to send water to the solar heater, which in turn would boost the chlorine production, whereas probably less chlorine would be necessary given the colder and therefore less sunny climate at that time. I guess I might be able to find an appropriately low SWG setting that would account for the higher flow rate during that season, although it sounds like it would mean lots more adjustments that usual.With solar and a variable speed pump it is generally worth getting an automation system that knows how to talk to the pump so it can raise the speed when in solar mode and lower it again when solar is off.
So with the goal of trying to be energy and cost efficient, this could actually be very inefficient if I have to maintain the pump at 2.0 hpís. So my questions are:
- 1. Does anybody know if there is a way to have Aqualink change the speed of a two-speed pump when the solar heater needs to run?
2. Would you agree that 0.25 hpís is too little to prime the solar system I was thinking of installing? I read in other posts people priming with around 0.5 hp, but I donít know about 0.25.
3. If so, would it make sense to switch out the pump e.g. for a 0.75 hp one? And if so, would there be any reason not to get a one-speed say 0.75 pump for the pool (again, I have a 3.0 hp pump for the spa, and I donít use the pool cleaner that uses the pump). I havenít looked into the cost of doing so, but maybe the solar heater installer could do so, and hopefully he might give me some value for the almost-new existing 2-speed pump.
4. Given the costs of a solar heater installation plus the fact that they are not free to use as they require higher pump settings, and installing one might make me need to consider changing my pump, maybe a solar heater is not as energy efficient and beneficial as initially thought. I have a natural gas heater, and natural gas is relatively inexpensive and clean. I wonder if anyone has compared the costs of regularly heating the pool with natural gas in a generally warm climate like South Florida versus the extra electricity of pumping water up to the roof for solar heating, possibly at a significantly higher horsepower setting than one would use otherwise.
Any help would be greatly appreciated!